1. Field of the Invention
The present invention relates to a camera having a focus detection means and a sight axis detection means and, more particularly, to an apparatus suitably used for a still camera, a video camera, an SV camera, and the like upon adjustment of a focusing state of a photographing system by selecting one of a plurality of in-focus signals obtained by the focus detection means having a function of detecting focusing states on a plurality of areas of an object.
2. Related Background Art
Conventionally, there have been proposed various cameras, in each of which an area in a finder field observed by a photographer, i.e., a so-called view direction of the photographer is detected by a sight axis detection means provided to a portion of a camera, and various photographing functions such as an auto-focusing function, an auto-exposure function, and the like are controlled on the basis of a signal from the sight axis detection means.
For example, Japanese Laid-Open Patent Application No. 61-61135 proposes a camera, which adjusts the focusing state of a photographing system by mechanically controlling the distance measuring direction of a focus detection device on the basis of an output signal from a sight axis detection means.
Also, the present applicant proposes, in Japanese Laid-Open Patent Application No. 1-241511, a camera, which comprises a sight axis detection means for detecting the view direction of a photographer, a focus detection means having a plurality of distance measuring fields, and an auto-exposure control means having a plurality of photometry sensitivity distributions, and controls the driving operations of the focus detection means and the auto-exposure control means on the basis of an output signal from the sight axis detection means.
In a conventional camera, photographing conditions for focus adjustment, exposure control, and the like are automatically set with reference to the central area in the finder field. In contrast to this, in the camera proposed by this patent, an arbitrary area (many areas in some cases) in the finder field is selected on the basis of a photographer's choice, and focus adjustment, exposure control, and the like are performed with reference to the selected area. Thus, one of the most important factors in image formation can be selected independently of automatic control methods, and a photographing operation can be performed under the desired conditions intended by a photographer.
In general, the movement of the sight axis of the photographer who observes the finder field is complex, and the sight axis position observed by the photographer does not always correspond to a main object, i.e., a distance measuring area to be focused.
For example, a photographer's attention is drawn to an especially bright object (having a high luminance) near the periphery of the frame, and the photographer may instantaneously observe the object.
In this case, when an auto-focusing operation is performed with reference to a distance measuring area selected on the basis of the sight axis information of the photographer, the driving operation of a focusing lens is very complicated, and the focusing state frequently changes (in particular, in a single-lens reflex camera).
As a result, a finder image cannot easily be observed, and the camera cannot be focused on the main target object.